Improvement in nut-and-bolt fastenings



L L. DUNLAP.

Improvement in Nut and Bol't Fastening.

, N0. 131,945. I Patented Oct- 8,1872.

UNITED STATES PATENT OFFICE.

LEWIS L. DUNLAP, OF PONTIAC, MICHIGAN.

IMPROVEMENT IN NUT-AND-BOLT FASTENINGS.

Specification forming part of Letters Patent No. 131,945, dated October 8, 1872.

To whom it may concern:

Be it known that I, LEWIS L. DUNLAP, of Pontiac, in the county of Oakland and State of Michigan, have invented a new and useful 7 Improvement in Incased Rubber J am-Nuts;

, top of my nut; Fig. 3 is a plan of the opposite side; and Fig. 4 is a transversevertical section.

Like letters refer to like parts in each figure.

The nature of this invention relates to the construction of an elastic jam-nutinclosed in a metallic case, and so constructed that the bolt will, in entering the nut, cut its own thread, and the case will not only protect the nut but also prevent undue expansion. The invention consists in constructing an elastic j am-nut with a tapering-hole, so that the bolt will free- 1y enter the bottom of the nut,and, in its further passage throughthe same, will cut its own thread and compress the nut in the case.

. In the accompanying drawing, Arepresents an India-rubber nut inclosed in a metallic case, B, into which the nut is pressed and held in place by the inwardly-projecting flanges b. The hole through the nut for the reception of the bolt is conical or taperin gin form, as shown at d in Fig. 4, the largest part of the hole being at the bottom of the nut, and of the proper diameter to freely receive the end of the bolt, which, in its progress through the nut, and owing to the peculiar shape of the hole, cuts its own thread in the nut, and still further compresses the same in the case and causes the nut so firmly to grasp the bolt that all dangerrof the former being accidentally loosened on the latter is entirely avoided.

What I claim 'as my invention, and desire to secure by Letters Patent, is-- The jam-nut described, consisting of the elastic nut A, having the tapering hole 01, inclosed in a metallic casing, as described.

LEWIS L. DUNLAP.

Witnesses:

THos. S. SPRAGUE, H. F. EBERTS. 

